Unity 之 c# 版的 CharacterMotor

using System;
using System.Collections;
using UnityEngine;

// This class just convert from CharacterMotor.js to C#

[RequireComponent(typeof(CharacterController))]
[AddComponentMenu("Character/Character Motor")]
public class CharacterMotor : MonoBehaviour
{
bool canControl = true;
bool useFixedUpdate = true;

// For the next variables, @System.NonSerialized tells Unity to not serialize the variable or show it in the inspector view.
// Very handy for organization!

// The current global direction we want the character to move in.
[NonSerialized]
public Vector3 inputMoveDirection = Vector3.zero;

// Is the jump button held down? We use this interface instead of checking
// for the jump button directly so this script can also be used by AIs.
[NonSerialized]
public bool inputJump = false;

class CharacterMotorMovement
{
// The maximum horizontal speed when moving
public float maxForwardSpeed = 10.0f;
public float maxSidewaysSpeed = 10.0f;
public float maxBackwardsSpeed = 10.0f;

// Curve for multiplying speed based on slope (negative = downwards)
public AnimationCurve slopeSpeedMultiplier = new AnimationCurve(new Keyframe(-90, 1), new Keyframe(0, 1), new Keyframe(90, 0));

// How fast does the character change speeds?  Higher is faster.
public float maxGroundAcceleration = 30.0f;
public float maxAirAcceleration = 20.0f;

// The gravity for the character
public float gravity = 10.0f;
public float maxFallSpeed = 20.0f;

// For the next variables, @System.NonSerialized tells Unity to not serialize the variable or show it in the inspector view.
// Very handy for organization!

// The last collision flags returned from controller.Move
[NonSerialized]
public CollisionFlags collisionFlags;

// We will keep track of the character's current velocity,
[NonSerialized]
public Vector3 velocity;

// This keeps track of our current velocity while we're not grounded
[NonSerialized]
public Vector3 frameVelocity = Vector3.zero;

[NonSerialized]
public Vector3 hitPoint = Vector3.zero;

[NonSerialized]
public Vector3 lastHitPoint = new Vector3(Mathf.Infinity, 0, 0);
}

CharacterMotorMovement movement = new CharacterMotorMovement();
enum MovementTransferOnJump
{
None, // The jump is not affected by velocity of floor at all.
InitTransfer, // Jump gets its initial velocity from the floor, then gradualy comes to a stop.
PermaTransfer, // Jump gets its initial velocity from the floor, and keeps that velocity until landing.
PermaLocked // Jump is relative to the movement of the last touched floor and will move together with that floor.
}

// We will contain all the jumping related variables in one helper class for clarity.
class CharacterMotorJumping
{
// Can the character jump?
public bool enabled = true;

// How high do we jump when pressing jump and letting go immediately
public float baseHeight = 1.6f;

// We add extraHeight units (meters) on top when holding the button down longer while jumping
public float extraHeight = 1.6f;

// How much does the character jump out perpendicular to the surface on walkable surfaces?
// 0 means a fully vertical jump and 1 means fully perpendicular.
public float perpAmount = 2.0f;

// How much does the character jump out perpendicular to the surface on too steep surfaces?
// 0 means a fully vertical jump and 1 means fully perpendicular.
public float steepPerpAmount = 1.5f;

// For the next variables, @System.NonSerialized tells Unity to not serialize the variable or show it in the inspector view.
// Very handy for organization!

// Are we jumping? (Initiated with jump button and not grounded yet)
// To see if we are just in the air (initiated by jumping OR falling) see the grounded variable.
[NonSerialized]
public bool jumping = false;

[NonSerialized]
public bool holdingJumpButton = false;

// the time we jumped at (Used to determine for how long to apply extra jump power after jumping.)
[NonSerialized]
public float lastStartTime = 0.0f;

[NonSerialized]
public float lastButtonDownTime = -100f;

[NonSerialized]
public Vector3 jumpDir = Vector3.up;
}

CharacterMotorJumping jumping = new CharacterMotorJumping();
class CharacterMotorMovingPlatform
{
public bool enabled = true;

public MovementTransferOnJump movementTransfer = MovementTransferOnJump.PermaTransfer;

[NonSerialized]
public Transform hitPlatform;

[NonSerialized]
public Transform activePlatform;

[NonSerialized]
public Vector3 activeLocalPoint;

[NonSerialized]
public Vector3 activeGlobalPoint;

[NonSerialized]
public Quaternion activeLocalRotation;

[NonSerialized]
public Quaternion activeGlobalRotation;

[NonSerialized]
public Matrix4x4 lastMatrix;

[NonSerialized]
public Vector3 platformVelocity;

[NonSerialized]
public bool newPlatform;
}

CharacterMotorMovingPlatform movingPlatform = new CharacterMotorMovingPlatform();

class CharacterMotorSliding
{
// Does the character slide on too steep surfaces?
public bool enabled = true;

// How fast does the character slide on steep surfaces?
public float slidingSpeed = 15f;

// How much can the player control the sliding direction?
// If the value is 0.5 the player can slide sideways with half the speed of the downwards sliding speed.
public float sidewaysControl = 1.0f;

// How much can the player influence the sliding speed?
// If the value is 0.5 the player can speed the sliding up to 150% or slow it down to 50%.
public float speedControl = 0.4f;
}

CharacterMotorSliding sliding = new CharacterMotorSliding();

[NonSerialized]
public bool grounded = true;

[NonSerialized]
public Vector3 groundNormal = Vector3.zero;

Vector3 lastGroundNormal = Vector3.zero;

Transform tr;

CharacterController controller;

void Awake()
{
controller = gameObject.GetComponent<CharacterController>();
tr = transform;
}

private void UpdateFunction()
{
// We copy the actual velocity into a temporary variable that we can manipulate.
var velocity = movement.velocity;

// Update velocity based on input
velocity = ApplyInputVelocityChange(velocity);

// Apply gravity and jumping force
velocity = ApplyGravityAndJumping(velocity);

// Moving platform support
var moveDistance = Vector3.zero;
if (MoveWithPlatform())
{
var newGlobalPoint = movingPlatform.activePlatform.TransformPoint(movingPlatform.activeLocalPoint);
moveDistance = (newGlobalPoint - movingPlatform.activeGlobalPoint);
if (moveDistance != Vector3.zero)
controller.Move(moveDistance);

// Support moving platform rotation as well:
var newGlobalRotation = movingPlatform.activePlatform.rotation * movingPlatform.activeLocalRotation;
var rotationDiff = newGlobalRotation * Quaternion.Inverse(movingPlatform.activeGlobalRotation);

var yRotation = rotationDiff.eulerAngles.y;
if (yRotation != 0)
{
// Prevent rotation of the local up vector
tr.Rotate(0, yRotation, 0);
}
}

// Save lastPosition for velocity calculation.
var lastPosition = tr.position;

// We always want the movement to be framerate independent.  Multiplying by Time.deltaTime does this.
var currentMovementOffset = velocity * Time.deltaTime;

// Find out how much we need to push towards the ground to avoid loosing grouning
// when walking down a step or over a sharp change in slope.
var pushDownOffset = Mathf.Max(controller.stepOffset, new Vector3(currentMovementOffset.x, 0, currentMovementOffset.z).magnitude);
if (grounded)
currentMovementOffset -= pushDownOffset * Vector3.up;

// Reset variables that will be set by collision function
movingPlatform.hitPlatform = null;
groundNormal = Vector3.zero;

// Move our character!
movement.collisionFlags = controller.Move(currentMovementOffset);

movement.lastHitPoint = movement.hitPoint;
lastGroundNormal = groundNormal;

if (movingPlatform.enabled && movingPlatform.activePlatform != movingPlatform.hitPlatform)
{
if (movingPlatform.hitPlatform != null)
{
movingPlatform.activePlatform = movingPlatform.hitPlatform;
movingPlatform.lastMatrix = movingPlatform.hitPlatform.localToWorldMatrix;
movingPlatform.newPlatform = true;
}
}

// Calculate the velocity based on the current and previous position.
// This means our velocity will only be the amount the character actually moved as a result of collisions.
var oldHVelocity = new Vector3(velocity.x, 0, velocity.z);
movement.velocity = (tr.position - lastPosition) / Time.deltaTime;
var newHVelocity = new Vector3(movement.velocity.x, 0, movement.velocity.z);

// The CharacterController can be moved in unwanted directions when colliding with things.
// We want to prevent this from influencing the recorded velocity.
if (oldHVelocity == Vector3.zero)
{
movement.velocity = new Vector3(0, movement.velocity.y, 0);
}
else
{
var projectedNewVelocity = Vector3.Dot(newHVelocity, oldHVelocity) / oldHVelocity.sqrMagnitude;
movement.velocity = oldHVelocity * Mathf.Clamp01(projectedNewVelocity) + movement.velocity.y * Vector3.up;
}

if (movement.velocity.y < velocity.y - 0.001)
{
if (movement.velocity.y < 0)
{
// Something is forcing the CharacterController down faster than it should.
// Ignore this
movement.velocity.y = velocity.y;
}
else
{
// The upwards movement of the CharacterController has been blocked.
// This is treated like a ceiling collision - stop further jumping here.
jumping.holdingJumpButton = false;
}
}

// We were grounded but just loosed grounding
if (grounded && !IsGroundedTest())
{
grounded = false;

// Apply inertia from platform
if (movingPlatform.enabled &&
(movingPlatform.movementTransfer == MovementTransferOnJump.InitTransfer ||
movingPlatform.movementTransfer == MovementTransferOnJump.PermaTransfer)
)
{
movement.frameVelocity = movingPlatform.platformVelocity;
movement.velocity += movingPlatform.platformVelocity;
}

SendMessage("OnFall", SendMessageOptions.DontRequireReceiver);
// We pushed the character down to ensure it would stay on the ground if there was any.
// But there wasn't so now we cancel the downwards offset to make the fall smoother.
tr.position += pushDownOffset * Vector3.up;
}
// We were not grounded but just landed on something
else if (!grounded && IsGroundedTest())
{
grounded = true;
jumping.jumping = false;
SubtractNewPlatformVelocity();

SendMessage("OnLand", SendMessageOptions.DontRequireReceiver);
}

// Moving platforms support
if (MoveWithPlatform())
{
// Use the center of the lower half sphere of the capsule as reference point.
// This works best when the character is standing on moving tilting platforms.
movingPlatform.activeGlobalPoint = tr.position + Vector3.up * (controller.center.y - (controller.height * 0.5f) + controller.radius);
movingPlatform.activeLocalPoint = movingPlatform.activePlatform.InverseTransformPoint(movingPlatform.activeGlobalPoint);

// Support moving platform rotation as well:
movingPlatform.activeGlobalRotation = tr.rotation;
movingPlatform.activeLocalRotation = Quaternion.Inverse(movingPlatform.activePlatform.rotation) * movingPlatform.activeGlobalRotation;
}
}

void FixedUpdate()
{
if (movingPlatform.enabled)
{
if (movingPlatform.activePlatform != null)
{
if (!movingPlatform.newPlatform)
{
movingPlatform.platformVelocity = (
movingPlatform.activePlatform.localToWorldMatrix.MultiplyPoint3x4(movingPlatform.activeLocalPoint)
- movingPlatform.lastMatrix.MultiplyPoint3x4(movingPlatform.activeLocalPoint)
) / Time.deltaTime;
}
movingPlatform.lastMatrix = movingPlatform.activePlatform.localToWorldMatrix;
movingPlatform.newPlatform = false;
}
else
{
movingPlatform.platformVelocity = Vector3.zero;
}
}

if (useFixedUpdate)
UpdateFunction();
}

void Update()
{
if (!useFixedUpdate)
UpdateFunction();
}

Vector3 ApplyInputVelocityChange(Vector3 velocity)
{
if (!canControl)
inputMoveDirection = Vector3.zero;

// Find desired velocity
Vector3 desiredVelocity;
if (grounded && TooSteep())
{
// The direction we're sliding in
desiredVelocity = new Vector3(groundNormal.x, 0, groundNormal.z).normalized;
// Find the input movement direction projected onto the sliding direction
var projectedMoveDir = Vector3.Project(inputMoveDirection, desiredVelocity);
// Add the sliding direction, the spped control, and the sideways control vectors
desiredVelocity = desiredVelocity + projectedMoveDir * sliding.speedControl + (inputMoveDirection - projectedMoveDir) * sliding.sidewaysControl;
// Multiply with the sliding speed
desiredVelocity *= sliding.slidingSpeed;
}
else
desiredVelocity = GetDesiredHorizontalVelocity();

if (movingPlatform.enabled && movingPlatform.movementTransfer == MovementTransferOnJump.PermaTransfer)
{
desiredVelocity += movement.frameVelocity;
desiredVelocity.y = 0;
}

if (grounded)
desiredVelocity = AdjustGroundVelocityToNormal(desiredVelocity, groundNormal);
else
velocity.y = 0;

// Enforce max velocity change
var maxVelocityChange = GetMaxAcceleration(grounded) * Time.deltaTime;
var velocityChangeVector = (desiredVelocity - velocity);
if (velocityChangeVector.sqrMagnitude > maxVelocityChange * maxVelocityChange)
{
velocityChangeVector = velocityChangeVector.normalized * maxVelocityChange;
}
// If we're in the air and don't have control, don't apply any velocity change at all.
// If we're on the ground and don't have control we do apply it - it will correspond to friction.
if (grounded || canControl)
velocity += velocityChangeVector;

if (grounded)
{
// When going uphill, the CharacterController will automatically move up by the needed amount.
// Not moving it upwards manually prevent risk of lifting off from the ground.
// When going downhill, DO move down manually, as gravity is not enough on steep hills.
velocity.y = Mathf.Min(velocity.y, 0);
}

return velocity;
}

Vector3 ApplyGravityAndJumping(Vector3 velocity)
{
if (!inputJump || !canControl)
{
jumping.holdingJumpButton = false;
jumping.lastButtonDownTime = -100;
}

if (inputJump && jumping.lastButtonDownTime < 0 && canControl)
jumping.lastButtonDownTime = Time.time;

if (grounded)
velocity.y = Mathf.Min(0, velocity.y) - movement.gravity * Time.deltaTime;
else
{
velocity.y = movement.velocity.y - movement.gravity * Time.deltaTime * 2;

// When jumping up we don't apply gravity for some time when the user is holding the jump button.
// This gives more control over jump height by pressing the button longer.
if (jumping.jumping && jumping.holdingJumpButton)
{
// Calculate the duration that the extra jump force should have effect.
// If we're still less than that duration after the jumping time, apply the force.
if (Time.time < jumping.lastStartTime + jumping.extraHeight / CalculateJumpVerticalSpeed(jumping.baseHeight))
{
// Negate the gravity we just applied, except we push in jumpDir rather than jump upwards.
velocity += jumping.jumpDir * movement.gravity * Time.deltaTime;
}
}

// Make sure we don't fall any faster than maxFallSpeed. This gives our character a terminal velocity.
velocity.y = Mathf.Max(velocity.y, -movement.maxFallSpeed);
}

if (grounded)
{
// Jump only if the jump button was pressed down in the last 0.2 seconds.
// We use this check instead of checking if it's pressed down right now
// because players will often try to jump in the exact moment when hitting the ground after a jump
// and if they hit the button a fraction of a second too soon and no new jump happens as a consequence,
// it's confusing and it feels like the game is buggy.
if (jumping.enabled && canControl && (Time.time - jumping.lastButtonDownTime < 0.2))
{
grounded = false;
jumping.jumping = true;
jumping.lastStartTime = Time.time;
jumping.lastButtonDownTime = -100;
jumping.holdingJumpButton = true;

// Calculate the jumping direction
if (TooSteep())
jumping.jumpDir = Vector3.Slerp(Vector3.up, groundNormal, jumping.steepPerpAmount);
else
jumping.jumpDir = Vector3.Slerp(Vector3.up, groundNormal, jumping.perpAmount);

// Apply the jumping force to the velocity. Cancel any vertical velocity first.
velocity.y = 0;
velocity += jumping.jumpDir * CalculateJumpVerticalSpeed(jumping.baseHeight);

// Apply inertia from platform
if (movingPlatform.enabled &&
(movingPlatform.movementTransfer == MovementTransferOnJump.InitTransfer ||
movingPlatform.movementTransfer == MovementTransferOnJump.PermaTransfer)
)
{
movement.frameVelocity = movingPlatform.platformVelocity;
velocity += movingPlatform.platformVelocity;
}

SendMessage("OnJump", SendMessageOptions.DontRequireReceiver);
}
else
{
jumping.holdingJumpButton = false;
}
}

return velocity;
}

void OnControllerColliderHit(ControllerColliderHit hit)
{
if (hit.normal.y > 0 && hit.normal.y > groundNormal.y && hit.moveDirection.y < 0)
{
if ((hit.point - movement.lastHitPoint).sqrMagnitude > 0.001 || lastGroundNormal == Vector3.zero)
groundNormal = hit.normal;
else
groundNormal = lastGroundNormal;

movingPlatform.hitPlatform = hit.collider.transform;
movement.hitPoint = hit.point;
movement.frameVelocity = Vector3.zero;
}
}

private IEnumerable SubtractNewPlatformVelocity()
{
// When landing, subtract the velocity of the new ground from the character's velocity
// since movement in ground is relative to the movement of the ground.
if (movingPlatform.enabled &&
(movingPlatform.movementTransfer == MovementTransferOnJump.InitTransfer ||
movingPlatform.movementTransfer == MovementTransferOnJump.PermaTransfer)
)
{
// If we landed on a new platform, we have to wait for two FixedUpdates
// before we know the velocity of the platform under the character
if (movingPlatform.newPlatform)
{
var platform = movingPlatform.activePlatform;
yield return new WaitForFixedUpdate();
yield return new WaitForFixedUpdate();
if (grounded && platform == movingPlatform.activePlatform)
yield return 1;
}
movement.velocity -= movingPlatform.platformVelocity;
}
}

private bool MoveWithPlatform()
{
return movingPlatform.enabled
&& (grounded || movingPlatform.movementTransfer == MovementTransferOnJump.PermaLocked)
&& movingPlatform.activePlatform != null;
}

private Vector3 GetDesiredHorizontalVelocity()
{
// Find desired velocity
var desiredLocalDirection = tr.InverseTransformDirection(inputMoveDirection);
var maxSpeed = MaxSpeedInDirection(desiredLocalDirection);
if (grounded)
{
// Modify max speed on slopes based on slope speed multiplier curve
var movementSlopeAngle = Mathf.Asin(movement.velocity.normalized.y) * Mathf.Rad2Deg;
maxSpeed *= movement.slopeSpeedMultiplier.Evaluate(movementSlopeAngle);
}
return tr.TransformDirection(desiredLocalDirection * maxSpeed);
}

private Vector3 AdjustGroundVelocityToNormal(Vector3 hVelocity, Vector3 groundNormal)
{
var sideways = Vector3.Cross(Vector3.up, hVelocity);
return Vector3.Cross(sideways, groundNormal).normalized * hVelocity.magnitude;
}

private bool IsGroundedTest()
{
return groundNormal.y > 0.01;
}

float GetMaxAcceleration(bool grounded)
{
return grounded ? movement.maxGroundAcceleration : movement.maxAirAcceleration;
}

float CalculateJumpVerticalSpeed(float targetJumpHeight)
{
// From the jump height and gravity we deduce the upwards speed
// for the character to reach at the apex.
return Mathf.Sqrt(2 * targetJumpHeight * movement.gravity);
}

bool IsJumping()
{
return jumping.jumping;
}

bool IsSliding()
{
return (grounded && sliding.enabled && TooSteep());
}

bool IsTouchingCeiling()
{
return (movement.collisionFlags & CollisionFlags.CollidedAbove) != 0;
}

bool IsGrounded()
{
return grounded;
}

bool TooSteep()
{
return (groundNormal.y <= Mathf.Cos(controller.slopeLimit * Mathf.Deg2Rad));
}

Vector3 GetDirection()
{
return inputMoveDirection;
}

void SetControllable(bool controllable)
{
canControl = controllable;
}

// Project a direction onto elliptical quater segments based on forward, sideways, and backwards speed.
// The function returns the length of the resulting vector.
float MaxSpeedInDirection(Vector3 desiredMovementDirection)
{
if (desiredMovementDirection == Vector3.zero)
return 0;
else
{
var zAxisEllipseMultiplier = (desiredMovementDirection.z > 0 ? movement.maxForwardSpeed : movement.maxBackwardsSpeed) / movement.maxSidewaysSpeed;
var temp = new Vector3(desiredMovementDirection.x, 0, desiredMovementDirection.z / zAxisEllipseMultiplier).normalized;
var length = new Vector3(temp.x, 0, temp.z * zAxisEllipseMultiplier).magnitude * movement.maxSidewaysSpeed;
return length;
}
}

void SetVelocity(Vector3 velocity)
{
grounded = false;
movement.velocity = velocity;
movement.frameVelocity = Vector3.zero;
SendMessage("OnExternalVelocity");
}
}